/*
 *  cc_cmp_safe.c
 *  corecrypto
 *
 *  Created on 04/22/2014
 *
 *  Copyright (c) 2014,2015 Apple Inc. All rights reserved.
 *
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
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 */

#include <corecrypto/cc_priv.h>

int
cc_cmp_safe(size_t num, const void * ptr1, const void * ptr2)
{
	size_t i;
	const uint8_t *s = (const uint8_t *)ptr1;
	const uint8_t *t = (const uint8_t *)ptr2;
	uint8_t flag = ((num <= 0)?1:0); // If 0 return an error
	for (i = 0; i < num; i++) {
		flag |= (s[i] ^ t[i]);
	}
	CC_HEAVISIDE_STEP(flag, flag); // flag=(flag==0)?0:1;
	return flag; // 0 iff all bytes were equal, 1 if there is any difference
}
